A65 Lightning project......

[Bess]

Hi,
    Just retainers, I worry they might come adrift so don't use them.

I have never used a comb for the A65, I have for the A10.

The A65 push rods are real easy to fit, the rockers, spindles etc. are fitted after the head is in place and torqued down. Drop the push rods in place and then fit the rocker train (hopefully not losing the spindle springs and thrust washers in the push rod cavity another use for the grabber)

Best wishes...

[Mike Farmer]

 

I always stuff those 'orrible orifices' with large pieces of rag before starting to assemble little bits that may drop into them.

Mike

[geraldhattrick75]

Good stuff, all of which I'll use.

Talking of the head, I was planning on using the twin carb head that came with the factory (I guess) spares- once I had had the rear head bolt pillar cracks welded.

But, on the basis of expense, (the twin carb head is totally bereft of any valve gear) I'm thinking maybe I'll use the single carb head instead.

Is there much of a difference, in terms of riding enjoyment, between single or twin carbs? (it is being built in every other respect as a Lightning Clubman)

[ChrisG]

The word on the street is that the performance figures from the Lightning was only marginally better than the Thunderbolt. Consequently, unless the both carbs are set up perfectly, this difference could disappear quite quickly. Plus if you are replacing the carbs with new ones as a lot of folk do these days, it works out twice the price.
There is a cosmetic problem though if you are using the Lightning sidepanels. The cutaways for the pancake filters are largely redundant and leave an awkward gap that I think spoils it. Just my opinion of course, but the Thunderbolt side panels in steel are difficult to find.

[geraldhattrick75]

Yeah, I've read in a few magazines that the single carb arrangement makes for an easier starting/ more pleasant bike to ride.

I think it's going to be the way I go on this build as it means I can start making proper progress on the engine straightaway.. Valve grinding tomorrow then I can fit the barrels and the head is all ready for popping on. (I've never been a lover of composite head gaskets so I bought a few copper jobbies off eBay and annealed them)

(Doing it this way also means I've got a hundred of the queen's finest that can be put to better use on the build..... )


The carb that came with the single carb head is a mikuni ( need to confirm the model details later), which I figure to use.... (it must have worked once)

I'll look at the side panel issues when I get a lot further into the build- but I agree that when something doesn't look right, it's a bit jarring aesthetically.



Re the twin carb head, I can always look into that after I've got this thing up and running.

Thanks,
Dave

[ChrisG]

As you have a Mikuni already then don't mess about, fit that! Yes, the aesthetics re the side panels, it looks like a wide open gob with the single carb in the middle but as you say, this can be sorted later.
Solid Copper Gaskets annealed- definitely the way to go.
I bought some original old, old stock gasket sets from ebay, and they have composite gaskets. Dont ask me why......!!!

Chris

[Mike Farmer]

 

PM sent

Mike

[geraldhattrick75]

Responded to Mike.

[geraldhattrick75]

Re using the Mikuni- thanks for confirming the idea Chris....

Weird one today, I measured the valve springs and they were shorter than the BSA manual suggested they should be (1 7/16" inner (manual suggested 1 5/8") & 1 3/4" outer (manual says 2 1/32)).

Haynes manual said that the ones off mine are in fact correct for 1968 on..... Another factory mod done. Phew...

(Out of interest is it just that the valves are shorter on later models or are the heads slightly different?)

[Bess]

Hi,
    I feel confident the valve lengths never changed, but there are different heads and its important you identify which you have.

Also:

1963 - new guides were specified
1968 - inlet port was widened for Spitfire
1969 - new valve top collar and collets, 20deg not 15deg

There are lots of wrong springs out there. Wrong diameter coils or more coils will bind when compressed in the engine, this maybe worth reading:

https://www.classicbritishspares.com/blogs/news/replacement-bsa-a50-a65-valve-springs-1962-1972

I buy mine from SRM, expensive but I have never had a problem with them.

Best wishes...

[geraldhattrick75]

Thanks for that Bess- a really interesting read and indicative of the understandable confusion that surrounds some of these old bikes.

I'll stick with the present ones, given that they look to have been fitted at the factory....

Any problems though and I'll be back to that useful URL- which I've now saved.

[geraldhattrick75]

Ooh er missus, the engine now has the barrel and head on.... Still got to sort out the tappets and stuff.

And guess what?
Me, and a couple of mate's, fitted the pistons in the barrel and when I looked inside ... one of the came followers was missing- fell into the engine.

Barrel off and grabber + magnet  used till we located said offender.
(we got it right the second time round) 

Thanks again for all your guidance folks....

[geraldhattrick75]

Being a pit picky, I noticed that the barrel nuts and head nuts (external) look a bit, er, manky... (Black country for 'not aesthetically pleasing),. so I thought I'd buy some shinier looking ones.

Would I be correct in thinking that the base nuts are 5/16 BSC (26 tpi) and the head nuts are 3/8 BSC.

I'm guessing a bit here and would appreciate a bit more accuracy from you more knowledgable folk before I buy some prettier ones.

Thanks,
Dave.

[Bess]

Hi,
    Yes they are 5/16, 26tpi, part number 24-5160

Best wishes...

[Mike Farmer]

 

Did you put retaining clips on the cam followers.?

Mike